1. Field of the Invention
The present invention relates to a wireless IC device used for a radio frequency identification (RFID) system that performs data communication in a non-contact manner using electromagnetic waves, and a component for the wireless IC device.
2. Description of the Related Art
In recent years, an article management system has used an RFID system which includes a reader/writer that generates an induction field and a wireless IC device that stores predetermined information allocated to an article, and non-contact communication is established between the reader/writer and the wireless IC device to transmit the information therebetween.
FIGS. 1A and 1B are views that show an example of a non-contact IC tag (wireless IC device) in which an IC tag label is attached to an IC tag antenna, which is described in Japanese Unexamined Patent Application Publication No. 2003-243918. FIG. 1A is a plan view. FIG. 1B is an enlarged cross-sectional view taken along the line A-A in FIG. 1A. The non-contact IC tag antenna includes two separated antenna patterns 91 and 92. The antenna patterns 91 and 92 are each made of a layer of metal thin films.
Antennas 101 and 102 are provided on a label base material 82b of the non-contact IC tag label 82, and an IC chip is mounted thereon. The antennas 101 and 102 of the non-contact IC tag label 82 are arranged to be in contact with the antenna patterns 91 and 92 via an anisotropic conductive adhesive 84 to thereby define a non-contact IC tag 90.
A sealant film 83 is laminated on the label base material 82b to prevent peeling of the IC tag label, and finally, an IC tag attached package 81 is provided.
The non-contact IC tag disclosed in Japanese Unexamined Patent Application Publication No. 2003-243918 and the package provided with the non-contact IC tag have the following problems.
Because antenna patterns are formed in a process that is different from the process in which a package is formed, a process of producing an antenna is required. This causes the process to be lengthened and requires an additional member which increases the production costs of the package.
To obtain a sufficient radiation characteristic, it is necessary to increase the size of the antenna pattern, and, therefore, it is difficult to attach a tag to a small article.
Because a tag is disposed on the base material of an article and another film covers the surface of the tag, the thickness of the IC tag formation portion is increased.